Figure 2-17 gives the velocity of a particle moving on an $x$ axis. Is it constant or varying?

As two trains move along a track, their conductors suddenly notice that they are headed toward each other. Figure 2-27 gives their velocities $v$ as functions of time $t$ as the conductors slow the trains. The figure's vertical scaling is set by $v_s=40.0 \mathrm{~m} / \mathrm{s}$. The slowing processes begin when the trains are $200 \mathrm{~m}$ apart. What is their separation when both trains have stopped?

You are driving toward a traffic signal when it turns yellow. Your speed is the legal speed limit of $v_0=55 \mathrm{~km} / \mathrm{h}$; your best deceleration rate has the magnitude $a=5.18 \mathrm{~m} / \mathrm{s}^2$. Your best reaction time to begin braking is $T=0.75 \mathrm{~s}$. To avoid having the front of your car enter the intersection after the light turns red, should you brake to a stop or continue to move at $55 \mathrm{~km} / \mathrm{h}$ if the distance to the intersection and the duration of the yellow light are $32 \mathrm{~m}$ and $1.8 \mathrm{~s}$ ? Give an answer of brake, continue, either (if either strategy works), or neither (if neither strategy works).

You are driving toward a traffic signal when it turns yellow. Your speed is the legal speed limit of $v_0=55 \mathrm{~km} / \mathrm{h}$; your best deceleration rate has the magnitude $a=5.18 \mathrm{~m} / \mathrm{s}^2$. Your best reaction time to begin braking is $T=0.75 \mathrm{~s}$. To avoid having the front of your car enter the intersection after the light turns red, should you brake to a stop or continue to move at $55 \mathrm{~km} / \mathrm{h}$ if the distance to the intersection and the duration of the yellow light are $40 \mathrm{~m}$ and $2.8 \mathrm{~s}$ ? Give an answer of brake, continue, either (if either strategy works), or neither (if neither strategy works).

Cars $A$ and $B$ move in the same direction in adjacent lanes. The position $x$ of car $A$ is given in Fig. $2-26$, from time $t=0$ to $t=7.0 \mathrm{~s}$. The figure's vertical scaling is set by $x_s=32.0 \mathrm{~m}$. At $t$ $=0$, car $B$ is at $x=0$, with a velocity of $12 \mathrm{~m} / \mathrm{s}$ and a negative constant acceleration $a_B$. How many times will the cars be side by side if the magnitude of acceleration $a_B$ is less than the answer to part (a)?

Cars $A$ and $B$ move in the same direction in adjacent lanes. The position $x$ of car $A$ is given in Fig. $2-26$, from time $t=0$ to $t=7.0 \mathrm{~s}$. The figure's vertical scaling is set by $x_s=32.0 \mathrm{~m}$. At $t$ $=0$, car $B$ is at $x=0$, with a velocity of $12 \mathrm{~m} / \mathrm{s}$ and a negative constant acceleration $a_B$. How many times will the cars be side by side if the magnitude of acceleration $a_B$ is more than the answer to part (a)?

Cars $A$ and $B$ move in the same direction in adjacent lanes. The position $x$ of car $A$ is given in Fig. $2-26$, from time $t=0$ to $t=7.0 \mathrm{~s}$. The figure's vertical scaling is set by $x_s=32.0 \mathrm{~m}$. At $t$ $=0$, car $B$ is at $x=0$, with a velocity of $12 \mathrm{~m} / \mathrm{s}$ and a negative constant acceleration $a_B$. Sketch the position $x$ of car $B$ versus time $t$ on Fig. 2-26.

Cars $A$ and $B$ move in the same direction in adjacent lanes. The position $x$ of car $A$ is given in Fig. $2-26$, from time $t=0$ to $t=7.0 \mathrm{~s}$. The figure's vertical scaling is set by $x_s=32.0 \mathrm{~m}$. At $t$ $=0$, car $B$ is at $x=0$, with a velocity of $12 \mathrm{~m} / \mathrm{s}$ and a negative constant acceleration $a_B$. For that value of $a_B$, how many times are the cars side by side?

Cars $A$ and $B$ move in the same direction in adjacent lanes. The position $x$ of car $A$ is given in Fig. $2-26$, from time $t=0$ to $t=7.0 \mathrm{~s}$. The figure's vertical scaling is set by $x_s=32.0 \mathrm{~m}$. At $t$ $=0$, car $B$ is at $x=0$, with a velocity of $12 \mathrm{~m} / \mathrm{s}$ and a negative constant acceleration $a_B$. What must $a_B$ be such that the cars are (momentarily) side by side (momentarily at the same value of $x$ ) at $t=4.0$ s?

If the maximum acceleration that is tolerable for passengers in a subway train is $1.34 \mathrm{~m} / \mathrm{s}^2$ and subway stations are located 806 m apart. Graph $x, v$, and $a$ versus $t$ for the interval from one start-up to the next.

If the maximum acceleration that is tolerable for passengers in a subway train is $1.34 \mathrm{~m} / \mathrm{s}^2$ and subway stations are located 806 m apart. If a subway train stops for $20 \mathrm{~s}$ at each station, what is the maximum average speed of the train, from one start-up to the next?

If the maximum acceleration that is tolerable for passengers in a subway train is $1.34 \mathrm{~m} / \mathrm{s}^2$ and subway stations are located 806 m apart, what is the travel time between stations?

If the maximum acceleration that is tolerable for passengers in a subway train is $1.34 \mathrm{~m} / \mathrm{s}^2$ and subway stations are located 806 m apart, what is the maximum speed a subway train can attain between stations?

Figure 2-25 depicts the motion of a particle moving along an $x$ axis with a constant acceleration. The figure's vertical scaling is set by $x_s=6.0 \mathrm{~m}$. What is the direction of the particle's acceleration?